首页 > 代码库 > Objective-C 学习记录6--dictionary

Objective-C 学习记录6--dictionary

2024-07-17 09:57:43   220人阅读

1.NSDictionary 和NSMutableDictionary

 

NSDictionary dictionaryWithObjectsAndKeys:~,nil

使用键值对创建字典,用nil标志结束

NSDictionary initWithObjectsAndKeys:

使用键值对初始化字典,也用nil来表示结束.

dictionary count  计算其字典的长度.

dictionary keyEunmerator  将key全部存在NSEunmerator中,可以快速枚举其中的key的值.

dictionary objectForKey: key  通过key来查询值.

demo:

    #import <UIKit/UIKit.h>     #import "MyClass.h"     int main(int argc, char *argv[])     {         NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];                //添加我们的测试代码                  NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:@"我是值",@"我是key1",@"我是值2",@"我是key2", nil];                  //得到词典的数量         int count = [dictionary count];         NSLog(@"词典的数量为： %d",count);                  //得到词典中所有KEY值         NSEnumerator * enumeratorKey = [dictionary keyEnumerator];                  //快速枚举遍历所有KEY的值         for (NSObject *object in enumeratorKey) {             NSLog(@"遍历KEY的值: %@",object);         }                  //得到词典中所有Value值          NSEnumerator * enumeratorValue =http://www.mamicode.com/ [dictionary objectEnumerator];                  //快速枚举遍历所有Value的值         for (NSObject *object in enumeratorValue) {             NSLog(@"遍历Value的值: %@",object);         }                  //通过KEY找到value         NSObject *object = [dictionary objectForKey:@"我是key2"];                  if (object != nil) {             NSLog(@"通过KEY找到的value是: %@",object);         }                                    int retVal = UIApplicationMain(argc, argv, nil, nil);         [pool release];         return retVal;     }

 

2.NSMutableDictionary是NSDictionary的子类,因此也继承其有的方法.

 

[NSMutableDictionary dictionaryWithCapacity:10];
//创建一个长度为10的字典,不过字典的内容超过了10会自动增加.
[NSMutableDictionary initWithCapacity: 10];//初始化长度为10;[dictionary setObject:~ forKey;~];//x向可变的字典中添加数据;[dictionary removeAllobjects];//删除所有的数据;removeObjectForKey: //删除key的对应值;
    #import <UIKit/UIKit.h>     #import "MyClass.h"     int main(int argc, char *argv[])     {         NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];                //添加我们的测试代码                  //创建词典对象，初始化长度为10         NSMutableDictionary *dictionary = [NSMutableDictionary dictionaryWithCapacity:10];                 //向词典中动态添加数据         [dictionary setObject:@"被添加的value1" forKey:@"key1"];                  [dictionary setObject:@"被添加的value2" forKey:@"key2"];                           //通过KEY找到value         NSObject *object = [dictionary objectForKey:@"key2"];                  if (object != nil) {             NSLog(@"通过KEY找到的value是: %@",object);         }                                    int retVal = UIApplicationMain(argc, argv, nil, nil);         [pool release];         return retVal;     }

 

 
[NSMutableDictionary dictionaryWithCapacity:10];
//创建一个长度为10的字典,不过字典的内容超过了10会自动增加.


联系
我们